Auto merge of #13769 - jonas-schievink:parse-half-open-range-pat, r=jonas-schievink

feat: Parse half-open `..= X` patterns

Closes https://github.com/rust-lang/rust-analyzer/issues/13739

crates/parser/src/grammar/patterns.rs

@@ -62,7 +62,6 @@ fn pattern_r(p: &mut Parser<'_>, recovery_set: TokenSet) {
 }
 
 fn pattern_single_r(p: &mut Parser<'_>, recovery_set: TokenSet) {
-    if let Some(lhs) = atom_pat(p, recovery_set) {
     // test range_pat
     // fn main() {
     //     match 92 {
@@ -70,31 +69,43 @@ fn pattern_single_r(p: &mut Parser<'_>, recovery_set: TokenSet) {
     //         101 ..= 200 => (),
     //         200 .. 301 => (),
     //         302 .. => (),
+    //         ..= 303 => (),
     //     }
     //
     //     match Some(10 as u8) {
     //         Some(0) | None => (),
-        //         Some(1..) => ()
+    //         Some(1..) => (),
+    //         Some(..=2) => (),
     //     }
     //
     //     match () {
     //         S { a: 0 } => (),
     //         S { a: 1.. } => (),
+    //         S { a: ..=2 } => (),
     //     }
     //
     //     match () {
     //         [0] => (),
     //         [1..] => (),
+    //         [..=2] => (),
     //     }
     //
     //     match (10 as u8, 5 as u8) {
     //         (0, _) => (),
-        //         (1.., _) => ()
+    //         (1.., _) => (),
+    //         (..=2, _) => (),
     //     }
     // }
 
-        // FIXME: support half_open_range_patterns (`..=2`),
+    if p.at(T![..=]) {
-        // exclusive_range_pattern (`..5`) with missing lhs
+        let m = p.start();
+        p.bump(T![..=]);
+        atom_pat(p, recovery_set);
+        m.complete(p, RANGE_PAT);
+        return;
+    }
+
+    if let Some(lhs) = atom_pat(p, recovery_set) {
         for range_op in [T![...], T![..=], T![..]] {
             if p.at(range_op) {
                 let m = lhs.precede(p);

crates/parser/src/parser.rs

@@ -162,7 +162,7 @@ impl<'t> Parser<'t> {
         Marker::new(pos)
     }
 
-    /// Consume the next token if `kind` matches.
+    /// Consume the next token. Panics if the parser isn't currently at `kind`.
     pub(crate) fn bump(&mut self, kind: SyntaxKind) {
         assert!(self.eat(kind));
     }

crates/parser/test_data/parser/inline/ok/0058_range_pat.rast

@@ -94,6 +94,21 @@ SOURCE_FILE
                   R_PAREN ")"
                 COMMA ","
               WHITESPACE "\n        "
+              MATCH_ARM
+                RANGE_PAT
+                  DOT2EQ "..="
+                  WHITESPACE " "
+                  LITERAL_PAT
+                    LITERAL
+                      INT_NUMBER "303"
+                WHITESPACE " "
+                FAT_ARROW "=>"
+                WHITESPACE " "
+                TUPLE_EXPR
+                  L_PAREN "("
+                  R_PAREN ")"
+                COMMA ","
+              WHITESPACE "\n    "
               R_CURLY "}"
         WHITESPACE "\n\n    "
         EXPR_STMT
@@ -169,6 +184,28 @@ SOURCE_FILE
                 TUPLE_EXPR
                   L_PAREN "("
                   R_PAREN ")"
+                COMMA ","
+              WHITESPACE "\n        "
+              MATCH_ARM
+                TUPLE_STRUCT_PAT
+                  PATH
+                    PATH_SEGMENT
+                      NAME_REF
+                        IDENT "Some"
+                  L_PAREN "("
+                  RANGE_PAT
+                    DOT2EQ "..="
+                    LITERAL_PAT
+                      LITERAL
+                        INT_NUMBER "2"
+                  R_PAREN ")"
+                WHITESPACE " "
+                FAT_ARROW "=>"
+                WHITESPACE " "
+                TUPLE_EXPR
+                  L_PAREN "("
+                  R_PAREN ")"
+                COMMA ","
               WHITESPACE "\n    "
               R_CURLY "}"
         WHITESPACE "\n\n    "
@@ -241,6 +278,36 @@ SOURCE_FILE
                   R_PAREN ")"
                 COMMA ","
               WHITESPACE "\n        "
+              MATCH_ARM
+                RECORD_PAT
+                  PATH
+                    PATH_SEGMENT
+                      NAME_REF
+                        IDENT "S"
+                  WHITESPACE " "
+                  RECORD_PAT_FIELD_LIST
+                    L_CURLY "{"
+                    WHITESPACE " "
+                    RECORD_PAT_FIELD
+                      NAME_REF
+                        IDENT "a"
+                      COLON ":"
+                      WHITESPACE " "
+                      RANGE_PAT
+                        DOT2EQ "..="
+                        LITERAL_PAT
+                          LITERAL
+                            INT_NUMBER "2"
+                    WHITESPACE " "
+                    R_CURLY "}"
+                WHITESPACE " "
+                FAT_ARROW "=>"
+                WHITESPACE " "
+                TUPLE_EXPR
+                  L_PAREN "("
+                  R_PAREN ")"
+                COMMA ","
+              WHITESPACE "\n    "
               R_CURLY "}"
         WHITESPACE "\n\n    "
         EXPR_STMT
@@ -286,6 +353,23 @@ SOURCE_FILE
                   R_PAREN ")"
                 COMMA ","
               WHITESPACE "\n        "
+              MATCH_ARM
+                SLICE_PAT
+                  L_BRACK "["
+                  RANGE_PAT
+                    DOT2EQ "..="
+                    LITERAL_PAT
+                      LITERAL
+                        INT_NUMBER "2"
+                  R_BRACK "]"
+                WHITESPACE " "
+                FAT_ARROW "=>"
+                WHITESPACE " "
+                TUPLE_EXPR
+                  L_PAREN "("
+                  R_PAREN ")"
+                COMMA ","
+              WHITESPACE "\n    "
               R_CURLY "}"
         WHITESPACE "\n\n    "
         MATCH_EXPR
@@ -360,6 +444,28 @@ SOURCE_FILE
               TUPLE_EXPR
                 L_PAREN "("
                 R_PAREN ")"
+              COMMA ","
+            WHITESPACE "\n        "
+            MATCH_ARM
+              TUPLE_PAT
+                L_PAREN "("
+                RANGE_PAT
+                  DOT2EQ "..="
+                  LITERAL_PAT
+                    LITERAL
+                      INT_NUMBER "2"
+                COMMA ","
+                WHITESPACE " "
+                WILDCARD_PAT
+                  UNDERSCORE "_"
+                R_PAREN ")"
+              WHITESPACE " "
+              FAT_ARROW "=>"
+              WHITESPACE " "
+              TUPLE_EXPR
+                L_PAREN "("
+                R_PAREN ")"
+              COMMA ","
             WHITESPACE "\n    "
             R_CURLY "}"
         WHITESPACE "\n"

crates/parser/test_data/parser/inline/ok/0058_range_pat.rs

@@ -4,25 +4,30 @@ fn main() {
         101 ..= 200 => (),
         200 .. 301 => (),
         302 .. => (),
+        ..= 303 => (),
     }
 
     match Some(10 as u8) {
         Some(0) | None => (),
-        Some(1..) => ()
+        Some(1..) => (),
+        Some(..=2) => (),
     }
 
     match () {
         S { a: 0 } => (),
         S { a: 1.. } => (),
+        S { a: ..=2 } => (),
     }
 
     match () {
         [0] => (),
         [1..] => (),
+        [..=2] => (),
     }
 
     match (10 as u8, 5 as u8) {
         (0, _) => (),
-        (1.., _) => ()
+        (1.., _) => (),
+        (..=2, _) => (),
     }
 }